Since you are practicing a set exercise, it is a bit easier to get used to anticipating your partner, but then again, it should be no different in the light or the dark.

At someplace or sometime, your vision will be impaired or of no use, so getting the feel of bodies in the dark, and being able to sense the movement of those bodies when touched should always be in your mind when training.

Oblique angles are the main entry to every technique your learn ... there is no head on colision of forces, just the oblique entry and redirection in nearly every Aikido technique.

Sometimes, sensing or figuring out where you are to "get the hell out of the way" is the key to actually being proficient in training with your eyes closed.

I kind of like walking through four or more of the class in the dark as they walk across the mat. It adjusts your ability to weave in and out of people without seeing them, and really helps when training in the dark to feel where uke or nage is standing. Position is everything to moving onto a technique.

Gotta love it.

Now, if you video tape your practice with an infrared camera, you will really see some comedy.